docs: def github_gfonts_ttFont(ttFont, license):
    """Get a TTFont object of a font downloaded
       from Google Fonts git repository.
    """
    if not license:
      return
  
    from fontbakery.utils import download_file
    from fontTools.ttLib import TTFont
    from urllib.request import HTTPError
    LICENSE_DIRECTORY = {
      "OFL.txt": "ofl",
      "UFL.txt": "ufl",
      "LICENSE.txt": "apache"
    }
    filename = os.path.basename(ttFont.reader.file.name)
    fontname = filename.split('-')[0].lower()
    url = ("https://github.com/google/fonts/raw/master"
           "/{}/{}/{}").format(LICENSE_DIRECTORY[license],
                               fontname,
                               filename)
    try:
      fontfile = download_file(url)
      return TTFont(fontfile)
    except HTTPError:
      return None